A sealing device of a hub unit bearing is provided at both axial end portions of the fixed ring and the rotating ring of the bearing. The sealing device prevents leakage of grease sealed in a bearing space and also prevents dust, water, and mud from entering the bearing space (see, for example, Patent Document 1).
For example, as illustrated in FIG. 12, a conventional sealing device 100 has an L-shaped slinger 101 to be fit onto the inner circumferential surface of an end portion of a fixed ring 110, an L-shaped slinger 102 to be fit onto the outer circumferential surface of an end portion of a rotating ring 120, and a sealing portion 103 which is bond-fixed to the slinger 101 and is slide-contacted with the slinger 192. The sealing portion 103 has an axial lip 103a slide-contacted axially with the slinger 102, and also has two radial lips 103b and 103c slide-contacted radially with the slinger 102. Also, in recent years, sealing devices have been increased, which are configured so that a magnetic encoder (e.g., a rubber magnet) 104 used as a sensor for an ABS of a vehicle is bond-fixed to a bearing outer side surface of the slinger 102 fit onto the outer circumferential surface of the rotating ring 110.
Patent Document 1: JP-A-2002-139057